Isomerization of 1-olefins to 2-olefins



3,531,545 ISOMERIZATION OF l-OLEFINS T0 Z-OLEFINS James W. Garner andBruce C. Benedict, Bartlesville,

Okla., assiguors to Phillips Petroleum Company, a corporation ofDelaware No Drawing. Filed Feb. 27, 1969, Ser. No. 803,094 Int. Cl. C07c5/24, 5/30 US. Cl. 260-683.2 12 Claims ABSTRACT OF THE DISCLOSUREIsomerization of l-olefins to 2-olefins over catalysts of the noblemetals of Group VIII on alumina in the presence of hydrogen. Sulfurcompounds effectively reduce hydrogenation of the olefins whilemaintaining double bond isomerization activity of the catalyst.

This invention relates to a process for the catalytic double bondisomerization of olefinic hydrocarbons. More specifically it relates toa process for the double bond isomerization of olefins in the presenceof hydrogen wherein the hydrocarbon mixture containing the olefinfurther contains sulfur compounds, naturally present or added, so as toeffectively reduce loss of olefins by hydrogenation while yet permittingmaximum double bond isomerization activity of the catalyst.

The process of the present invention is applicable to the treatment ofvarious unsaturated hydrocarbons, particularly to the unsaturatedhydrocarbons having a terminal double bond between two non-tertiarycarbon atoms. The term. non-tertiary indicates that the doublebondedcarbon atoms are non-tertiary, although the hydrocarbon may containtertiary carbon atoms remote from the double bonded carbon atoms. Theradicals attached to such tertiary carbon atoms may be of alkyl, aryl,or aralkyl type.

The particular unsaturated hydrocarbons to which this invention is mostapplicable are termed l-olefins and have a chain of at least four carbonatoms. Examples of such hydrocarbons include butene-l, pentene-l,hexene-l, and higher homologues; 3-methyl pentene-l, 4-methyl hexene-l,4-phenyl hexene-l, and the like. Of course, process stream hydrocarbonmixtures can be subjected to this invention Where such streams containmixtures of various l-olefins, or various l-olefins plus saturatedhydrocarbons.

Where the hydrocarbon feed stream to be subjected to double bondisomerization additionally contains unsaturated hydrocarbons such asdiolefins or polyolefins, or acetylenic impurities and the like,pretreatment by means known to the art should be employed to remove suchimpurities. If not removed beforehand, such impurities tend topolymerize during and to interfere with double bond isomerization, or tobe converted during the process to undesirable products or polymers.

Although the presence of saturated hydrocarbons corresponding to theolefins, such as butanes, pentanes, hexanes, and the like, is notdetrimental, the saturated hydrocarbons do have a diluting action on thetreated olefins. This invention may be practiced either in the presenceor absence of such diluting saturated hydrocarbons, depending upon theoverall concentration of olefin present or desired after theisomerization process.

It is the method of this invention to provide a process of isomerizingl-olefins to 2-olefins or internal olefins, such as isomerizing butene-lto butene-2, over a single catalyst, the isomerization being performedwithout interference by the presence of, and surprisingly With theeffective aid of, sulfur compounds.

Heretofore, sulfur-containing compounds in a hydro- United States Patent0 ice carbon feed stream have been considered as catalyst poisons,severely poisoning isomerization catalysts so as to greatly reduce andprevent effectiveness of double bond isomerization. Extensivepreliminary processes have been required to essentially eliminate thesulfur compounds before the isomerization step could proceed effectivelyand successfully. The advantages of the present invention over prior artprocesses include simplification of process equipment, simplification ofoperation, minimization of plant investment, and reduced operatingcosts.

By the method of this invention, there is provided a process forisomerizing a monoolefinic l-olefin hydrocarbon in a hydrocarbon streamalso containing sulfur compounds, the process comprising contacting thehydrocarbon stream containing the sulfur compounds at elevatedtemperature in the presence of hydrogen with a catalyst to convert atleast a portion of the l-olefins to internal olefins or 2-olefins.Further, by the method of this invention, there is provided a processfor adding sulfur-containing compounds to a hydrocarbon streamcontaining l-olefins, and thereafter contacting the hydrocarbon streamin the presence of hydrogen with a catalyst to convert at least aportion of the l-olefins to internal olefins or 2-olefins.

Specifically, by the method of this invention, the sulfur compounds,either present naturally in the hydrocarbon stream or added as acomponent to a hydrocarbon stream otherwise substantially free of sulfurcompounds, affect the properties of the catalysts of the process so thateffective double bond isomerization of the l-olefin is obtained Whilethe otherwise associated hydrogenation activity of the catalysts forolefins is substantially suppressed. Therefore, by this invention, lossof olefins to formation of saturated hydrocarbons by the associatedhydrogenation activity of the catalysts is substantially avoided, thuseffecting considerable savings in olefin, avoiding loss of the activeolefin feedstock to saturated hydrocarbons, and achieving valuablesavings in materials. These advantages are in addition to the largereduction in capital investment attained by reduction in processequipment through elimination of sulfur-removing treating steps asdisclosed hereinabove.

Accordingly, it is an object of this invention to provide an improvedolefin double bond isomerization process and improved olefin double bondisomerization catalysts.

It is also an object of this invention to provide an olefin double bondisomerization process in which the activity of the catalysts isbeneficially affected by a novel method of treatment.

Additional objects and advantages of this invention will become apparentfrom the descriptions and examples.

This invention can be carried out in any of the usual processsingmethods and sequences, including series or parallel flows of reactantsand similar modifications and adaptions generally applicable tohydrocarbon processing. Similarly, provision can be made for control ofprocess conditions by the usual instrumentation.

A typical hydrocarbon feed composition suitable for the process of thisinvention is a feed stream containing saturated hydrocarbons,isobutylene, butadiene, butene-Z in both the cis and trans forms,butene-l (the component desired to be isomerized to butene-Z), and minoramounts of diolefins. Another typical hydrocarbon feed stream is onecontaining propane, propylene, butanes, butenes, 3-methyl butene-l,2-methyl butene-l, 2-methyl butene-Z, and minor amounts of diolefinssuch as 1,3-butadiene. The process stream will either contain sulfurcompounds, organic or inorganic in type, one or more, or asulfurcontaining compound, one or more, will be added to the processstream, according to this invention.

Catalysts suitable for use in the process of this invention include thenoble metals of Group VIII of the Periodic Table of Elements, as listedin the Handbook of Chemistry and Physics, published by the ChemicalRubber Company, in the 49th edition (1969), page B3. The catalystsintended to be included in the group of noble metals of Group VIIIspecifically are ruthenium, rhodium, palladium, osmium, iridium, andplatinum, This invention is effective with the catalysts listed, and notwith the other metals of Group VIII, namely, iron, cobalt and nickel.Iron, cobalt, and nickel appear to undergo direct reactions with sulfurcompounds to form various metal sulfides. The noble metals of Group VIIIdo not react directly with sulfur compounds contained in the feed streamunder the temperatures of this invention, though their activity isdistinctively and surprisingly affected by the process of thisinvention.

Any of the usual catalyst supports can be employed, such as alumina(preferred), silica alumina, glass beads, and carbon. Both pelleted andspherical form catalysts are satisfactory.

A preferred catalyst is palladium on a carrier, the carrier preferablybeing alumina. The catalyst should contain from 0.005 to 1.0 percentpalladium on alumina, preferably about 0.01 to about 0.1 weight percentpalladium on alumina. The alumina carrier is of a controlled porediameter to contain about 41.5 weight percent aluminum. A suitablecatalyst weighs about to about 52 pounds per cubic foot, has a surfacearea of about 340 to about 350 square inches per gram, a pore volume ofabout 0.50 to about 0.60 ml. per gram, and a pore diameter of about 60to about 70 A.

A commercial catalyst satisfactory for use in this invention ismanufactured by Catalysts and Chemicals, Inc., Louisville, Kentucky,designated as catalyst C-31 and described in Bulletin No. C31053. Thecommercial catalyst contains about 0.05 Weight percent palladium onalumina.

Another commercial catalyst satisfactory for use in this invention ismanufactured by the Girdler Corporation, Louisville, Kentucky,designated as catalyst G-55 and described in Data Sheet G-55-562, andcontains about 0.03 weight percent palladium on alumina.

The process is conducted at a reaction temperature of about 275 to 500F., preferably 325-375 F. and such temperature range is critical to theprocess of this invention. Lower temperatures are ineffective. Highertemperatures tend to shift the catalytic equilibrium produced betweenthe l-olefin (feed stream) and the 2-olefin (desired product) away fromthe 2-olefin and toward the l-olefin, thus reducing the yield of thedesired 2-olefin.

This invention can be most effectively practiced at relatively lowpressure conditions while maintaining the hydrocarbon most preferably inthe vapor phase, although liquid phase operation can be used. Pressuresemployed are from about 15 to about 250 p.s.i.g., preferably from aboutto about 160 p.s.i.g. Hourly space velocities, VHSV, are maintained fromabout 100 to 10,000, preferably from about 1,000 to about 2,000, basedon standard conditions.

Hydrogen is required in the practice of this invention, preferably beingmixed with the hydrocarbon stream prior to contacting the stream withthe catalyst, preferably after vaporization of the hydrocarbon. Thehydrocarbon can be added undiluted, or added diluted with an inert gas.The hyrogen is necessary to effect double bond isomerization of thel-olefin with the catalysts of our process. The hydrogen is added inamounts from 0.1 to 5.0 mol percent, preferably in amounts of about 0.2to about 1.2 mol percent.

The process of this invention is applicable to a hydro carbon feedstream containing the l-olefin of which it is desired to convert thedouble bond to an internal position and wherein in the stream is alsofound, or is added, a sulfur compound. The sulfur compounds can be anynaturally occurring organic or inorganic sulfur compound that can beconveniently added, and may be in the form of gaseous, liquid, or solidmaterials under normal temperatures and pressures. Examples of suitablesulfur compounds include: sulfides, such as hydrogen sulfide, alkali andalkaline earth metal sulfides; thioalcohols (mercaptans) and alkali andalkaline earth metal salts thereof; thioethers; thioaldehydes;thioketones; disulfides, both organic and inorganic, such as alkali andalkaline earth disulfides; thionacids; thiolacids; dithioacids;thiourea; isothiocyanates; dithiocarbonates (xanthates); or the like. Inany of which compound the organic component of the compound may have upto about 10 carbon atoms for alkyl, up to about 18 carbon atoms forcyclic, and be of alkyl, aryl, alkaryl, aralkyl type, and includevarious substituents on the chain or ring including halide, amino,carboxy, hydroxy, and the like.

The organic sulfur compound can be added as a gas, as a liquid, as avaporized solid, as a solution, in undiluted form, or in diluted form,using any convenient means known to the art to add a minor amount ofsuch a material to a hydrocarbon feed stream.

This invention, carried out within the ranges as described hereinbefore,is illustrated by the following examples. The examples, adapted to theisomerization of butene- 1 to butene-2, should be considered asillustrative of the general applicability of the process to thefeedstocks previously discussed, and without being limitative of theinvention.

EXAMPLE I A hydrocarbon stream was isomerized under the operatingconditions indicated below, using a palladium on alumina catalyst of thetype as described hereinbefore, at a temperature of 250 F., and in theabsence of a sulfur compound. It will be noted that butene-l isconverted to butene-2 under these conditions, but that, however, a highconsumption of hydrogen is shown by the formation of paraffins.

RUN NO. A

Process pressure p.s.i.g 110 Process temperature F 250 VHSV 1,000 Haddition mols per mols of hydrocabron 1.18 Sulfur compound none Streamanalysis (Mol percent unless noted) Feed Effluent stream compositionHydrogem 1 Nil P1 opylene 12.8 12. 42 Propane 1. 36 1. 74 iso-Butane.52. 9 51. 9 n-Butane 0. 30 1. 00 Butene-l 13. 9 3. 4 Butene-2 1. 5 29. 3Total 05 0. 24 0. -4 Butene-2/butene-1 rat 1. 4 8. 5 Butene-l conversion2 75 Parafiins formed, mols p 100 mols of Hy ocarbon 1. 07 Percent of H2consumed forming paraffin 2 91 1 Feed Stream composition given on ahydrogen-free basis. 2 Percent The above example shows that at atemperature of 250 F. and in the absence of the sulfur compound that thecatalyst is active both as a double bond isomerization catalyst and as ahydrogenation catalyst.

EXAMPLE II An embodiment of this invention was carried out with a feedstream containing butene-l so as to isomerize the butene-l to butene-Z,using the same catalyst and temperature as in Example I, except that thefeed stream here contained a sulfur compound.

RUN NO. B

Process pressure p.s.i.g 110 Process temperature F 250 VHSV 1,000 Haddition mols per 100 mols of hydrocarbon 1.18 Sulfur compound PresentStream analysis (Mol percent unless noted) Feed Effluent streamcomposition Hydrogen 1. 13 Ethane" 26. 59 26. 27 Propylene- 10. 8 10. 66Propane. 0.08 10. 1soButane 0. 03 0. 05 n-Butane 0. 03 0. 03iso-Butylene 3. 7 3. 64 Buteue-l 10.4 10.4 Butcne-2 14. 3 14. 1iso-Pentane- 0.06 0. 6 n-Pentane. 29. 2 28 3-methylbutene-1 2. 51 2.Z-methyl butene-l 0. 0. 2-n1ethyl butenc-2 2. 10 2. Butene-2/butene-1ratio 1. 4 1. Butene-l conversion 2 3-methy1butene-1 conversion 2Paraflins formed, mols per 100 mols of hydrocarbons 0. G H2 consumed informing parafiins.

1 Feed Stream composition given on a hydrogen-free basis.

2 Percent.

From the above example it will be observed that the presence of thesulfur compound at a temperature of 250 F. did dampen the hydrogenationactivity toward the l-olefins but also effectively and undesirablydestroyed the double bond isomerization properties of the catalyst.

EXAMPLE III RUNS NOS. C, D, AND E Run 0 Run D Run E Process Pressure,p.s.i.g 110 110 110 Process Temperature, F. 310 310 311 VHSV 1, 000 1,000 1, 000 Hz addition mols per 100 mols of hydrocarbon 1. 18 1. 18 1.18

Sulfur Compound 1 Present. CH SH, 10 molp.p.n1. 3 H25, 19 mol p.p.m.

Stream analysis (Mol percent unless noted) Feed stream Efliuentcomposition Runs C and D Run C Run D Hydrogen 1. 11 1. 14 Ethane. 24. 8824.6 24. 6 Propylene. 10. 8 10. 67 10. 69 Propane 0. 13 0. 14 0. 12iso-Butane 0.05 0. 07 0.08 n-Butane 0. 06 0. 08 0. 06 rso-Butylene. 3. 93. 84 3. 83 Butened 10. 7 6. 5 8. 2 Butane-2 14. 7 18. 6 17.0 1so-Pentan0. 06 0. 07 0.06 n-Pentane 29. 8 29. 46 29. 36 3-methyl butene 2. 55 1.16 1. 2-methyl butene 0. 29 0.34 0. 26 2-methyl butene 2 2.08 3. 36 2. 7Butene-1/butene-2 1a 0 .4 2.9 2. 1 Butene-l conversion 38 23 B-methylbutene-l con n 54 25 Paraffins formed, mols per of hydrocarbon 0. 06 0.03 H2 consumed in forming parafiins.. 5 3

1 Feed stream composition given on a hydrogen-free basis.

Stream analysis (M01 percent unless noted) Feed Effluent stream,composition, Run E un E Hydrogen 1. 10 Ethane 24. 56 26. 2 Propylene 11.O 10. 86 Propane 0. O9 0. 11 Iso-Butane 0. 04 0. 06 n-Butane 0. 05 0. 07Iso-Butylene 3. 9 3. 84 Butane-1 10. 0 6. 9 Butane-2 ,4. 6 17. 5Iso-Pentane 0. 06 0. 07 nPentane 28. 8 28. 45 3-methyl butcne-l 2. 64 1.94 2methyl buteue-l 0. 16 0. 1 2-methyl butene-Z 2. 10 2. 8Butene-2lbutene-1 ratio 1. 5 2. 5 Butene-l conversion 30 3-1nethylbutene-l conversion 26 Parailins formed, mols per 100 mols ofhydrocarbon- 0. 07 H2 consumed in forming paraliins- 6 1 Feed streamcomposition given on a hydrogen-free basis.

The data given in Example III above illustrate the effect of thepresence of sulfur compounds in the feed stream in combination withelevation of the process temperature to 310311 F. In Run C the specificsulfur compound was not identified but was positively present; in Run Dthe sulfur compound was CH SH present at 10 mol p.p.m.; in Run E thesulfur compound was H 8 present at 19 mol p.p.m. Example III data aboveshow that the high effectiveness of the combination of the presence of asulfur compound plus the elevation in temperature to 310-311 F.effectively permits double bond isomerization while equally effectivelysuppressing hydrogenation activity of the catalyst. The runs of ExamplesIII and IV also demonstrate effectiveness of both organic and inorganicsulfur to this invention.

1 OHESH, 10 mol p.p.m. 2 H28, 19 mol p.p.m.

Stream analysis (Mol percent unless noted) Feed stream Efiiuentcomposition Run F Run G Run F Run G Hydrogen- 1.12 1.09 Ethane. 24. 8826. 56 24. 6 26. 27 Propylen 10. 8 11. 0 10. 67 10. 85 Propane. 0. 130.09 0. 14 O. 12 iso-Butan 0. 05 0. 04 0. 06 0. 05 n-Butane O. 06 0. 050. 08 0. 08 iso-Butylen 3. 9 3. 9 3. 85 3. 85 Butene-1 10. 7 10. 0 5. 15. 5 Butene-2- l4. 7 14. 6 20. 0 18. 9 iso-Pentane 0. 06 O. 06 0. 07 0.07 n-Pentane 29. 8 28. 8 29. 46 28. 49 3-methyl butene- 2. 55 2. 640.70 1. 41 2-methyl butene-l. 0. 29 0. l6 0. 21 0. 16 2-methyl butane-2.2. O8 2. 10 3. 94 3. 34 Buten-Z/butene-l rati 1. 4 1.5 3. 9 3. 4 Butene-l conversion 52 44 3-methyl butane-1 conversion 72 46 Paraflinsformed, mols per 100 mols of hydrocarbon 0. 05 0. 08 H2 consumed informing parafiins 4 7 1 Feed stream composition given on a hydrogen-freebasis.

The above example further confirms the effectiveness of addition ofvarious types of sulfur compounds, at various addition amounts, and atsomewhat higher temperatures still within the range of the invention,showing even further improvement in percent of butene-l conversion whileyet maintaining extremely low percent of hydrogen consumption toformation of parafi'ins, thus illustrating the effectiveness of thesulfur compounds in suppressing hydrogenation activity of the catalystwhile yet maintaining full double bond isomerization activity.

The examples given in the disclosure show primarily conversion ofbutene-l to butene-2; these examples are not to be considered aslimiting the feedstock to which the present invention is applicable.

Reasonable variations and modifications are withi the scope of thedisclosure of this invention and would be made by those skilled in theart without departing from the scope and spirit of the presentinvention.

That Which is claimed is:

1. A method of treating a catalyst selected from the noble metals ofGroup VIII, said catalysts having both hydrogenation and double bondisomerization activity toward l-olefins, which comprises contacting saidcatalyst with a feed stream containing said l-olefins and at least onesulfur-containing compound at from about 275 to about 500 F. and therebysubstantially affecting the hydrogenation properties of said catalystwhile maintaining substantially the double bond isomerization propertiesof said catalyst.

2. A process for treating a hydrocarbon stream to isomerize l-olefinscontained in said stream to 2-olefins, the said stream furthercontaining sulfur compounds tending to cause loss of isomerizationproperties of an isomerization catalyst selected from the noble metalsof Group VIII, which comprises:

(a) mixing said hydrocarbon stream in the fluid state (b) heating themixture of hydrocarbon stream containing sulfur compounds and H to atemperature at from about 275 to about 500 F. sufiicient to maintaindouble bond isomerization properties of the catalyst while permittingthe sulfur compounds to substantially decrease the hydrogenationproperties of said catalyst,

(c) contacting the heated mixture with said catalyst, therebysubstantially decreasing the hydrogenation properties of the saidcatalyst and thereby substantially preventing loss of olefins byhydrogenation, and thereby maintaining maximum double bond isomerizationof the said 1-o1efins to 2-olefins,

(d) recovering the said 2-olefins as a product.

3. The process of claim 2 wherein the catalyst contains from about 0.005to about 1.0 percent palladium on alumina.

4. The process of claim 2 wherein step (c) is followed by:

(d) cooling the isomerized mixture,

(e) conducting the cooled mixture to a separation zone,

(f) separating the H from the isomerized monoolefins,

(g) recycling the separated H from step (f) to step (a), and

(h) recovering the isomerized monoolefin from step (f) as a product.

5. The process of claim 2 wherein the said sulfurcontaining compound instep (b) is added directly to the reaction zone.

6. The process of claim 2 wherein the said hydrocarbon stream alreadycontains a sulfur-containing compound and wherein in step (b) the amountof sulfur-containing compound there admixed is reduced accordingly.

7. The process of claim 6 wherein the amount of sulfur-containingcompound added in step (b) is from about 1 to about 50 mol ppm. assulfur.

10 8. A method of treating a catalyst selected from the noble metals ofGroup VIII, said catalysts having both double bond isomerization andhydrogenation properties in contacting a stream containing l-olefins,which comprises:

(a) admixing with said stream at least one sulfurcontaining compound andwith hydrogen,

(b) heating the stream from step (a) to a temperature at from about 275to about 500 F. suflicient to maintain double bond isomerizationproperties of said catalyst while substantially decreasing thehydrogenation properties of said catalyst,

(c) contacting the said catalyst with said heated mixture from step (b),thereby substantially decreasing the hydrogenation properties of saidcatalyst while substantially maintaining the double bond isomerizationproperties of said catalyst.

9. The method of claim 8 wherein the catalyst contains from about 0.005to about 1.0 weight percent palladium on alumina. 30 10. The method ofclaim 8 wherein the activity of the catalyst is affected by contactingwith said stream containing at least one sulfur-containing compound atfrom about 325 to about 375 F.

11. The process of claim 8 wherein the said hydrocarbon stream alreadycontains a sulfur-containing compound and wherein in step (a) the amountof sulfurcontaining compounds therein admixed is reduced accordingly.

12. The method of claim 8 wherein the amount of at least onesulfur-containing compound added in step (a) is from about 1 to about 50mol ppm. as sulfur.

References Cited UNITED STATES PATENTS 3,215,751 11/1965 Bourne 260683.23,290,404 12/1966 Howman 260-6832 3,182,097 5/1965 Brennan 260-68322,953,606 9/1960 Dean.

3,369,052 2/1968 Howell. 3,433,843 3/1969 Hoekstra.

3,408,415 10/1968 Dovell. 3,409,702 11/1968 Plonsker 260683.2 3,432,5643/1969 Hoekstra 260-666 3,409,682 11/1968 Mitsche 260666 DELBERT E.GANTZ, Primary Examiner VERONICA OKEEFE, Assistant Examiner

